The husband of a missing Michigan mom — last seen 13 days ago getting into a car at the end of her driveway — says that although she has run off before, he's worried that this time something may have happened to her.

"I pray she's with some guy than any of the other options," Stephen Grant told The Detroit Free Press in an interview, adding that he had no role in her mysterious disappearance.

"I have nothing to do with it," he said. "I miss her with everything I have."

Click here to read the Detroit Free Press story

Tara Lynn Grant was last seen the night of Feb. 9 after getting into an argument with her husband over a hectic work schedule that carried her to and from an office in Puerto Rico every week, keeping her away from her two young children. Tara packed a bag, then got into a dark car waiting for her at the end of their home's driveway, according to Stephen Grant.

She hasn't been heard from since, and none of her credit cards, nor her cell phone, have been used. Stephen Grant reported her missing on Feb. 14.

Click here to see an interview Stephen Grant gave local affiliate WXYZ-TV

Grant insisted his marriage was strong, but told the Free Press there have been two previous episodes when his wife left without any communication, but those instances were short-lived.

"Tara had gone black twice before, for a day or day and a half," he said, adding that a deputy used the terms "going dark, going black" when asking him whether his wife had ever been deliberately unreachable.

Authorities from the Macomb County Sheriff's Office this week investigated a series of e-mails purportedly exchanged between Stephen Grant and a former girlfriend late last month that the other woman turned over to authorities this week.

The risque e-mails, which were first reported by The Detroit News, were described by Stephen Grant to the Detroit Free Press as playful joking between former lovers.

"It was the kind of banter we had," he said.

They discuss an older man Stephen Grant says works with his wife, with whom she may have had a romantic relationship.

Here is an excerpt from the e-mails, as reported by The Detroit News:

Ex-girlfriend: "So what are you going to do about the cheatin' wife? ..."

Grant: "Don't know yet. By the way — she does talk to the 'old geezer' like that ... that is the problem. Actually, never that direct. Everyone is not as subtle as me. The problem is she says things in code. And because of that, I don't know what is actually going on. Also, and I thought I told you this, about two years ago, she did the same thing with some guy she used to know. Nothing physical, just txt and e-mail and phone calls ..."

Grant told the Detroit Free Press he had not seen the woman he was e-mailing for six years but kept in touch with her through e-mail and phone calls. He said the comments about an "old geezer" were based on an older man's attention toward his wife and not any suspicion of an affair.

Police investigated the e-mails, which were sent to the newspaper before they were sent to the media, Macomb County Sheriff Mark Hackel told FOXNews.com

"Our concern about it, truth or not — if he's talking to a girl about it two weeks before his wife's disappearance, how come he didn't talk to it about us?" Hackel asked.

Police questioned the man at Tara's workplace who may have been referenced in the e-mails, but said nothing came of that potential lead. They also questioned this same man earlier when attempting to locate Tara.

"We talked to him before, as well, and he was surprised at the statements [in the e-mails] as well. Absolutely, we're convinced that they're not true ... but we had to follow up on it," Hackel said of the idea of a romantic relationship between Tara and the man.

Hackel said that despite Stephen Grant's insistence that police have named him the top suspect in his wife's disappearance, police have never labeled him as that. Rather, Stephen Grant seems to be portraying himself in the media as a victim, Hackell added.

And police are frustrated with what they say is his lack of cooperation in the investigation, including the fact that he will only talk to them through his attorney via fax.

"It's a very cumbersome process and something we're not used to I guess, so you've just got to plod along and work with it," Hackel told FOXNews.com.

What police really want is access to the Grants' computer at home. They're hoping to find some communication exchanged between Tara and anyone who may have a clue to her whereabouts, or any other information that may be helpful in their search. But so far, they haven't been granted access by Stephen Grant.

"With someone who's missing a wife ... that sure changed in a short period of time so it appears now there's more of a focus on him not being looked at, not being questioned. That's not how an investigation works," Hackel said. "I think he finds that offensive but that's how it works. We have to ask the tough questions."

Stephen Grant's lawyer, David Griem, did not return phone calls by FOXNews.com.